Best Pulse Oximeter of 2021
A reputation for accuracy, impressive performance in our consistency testing, and low price point make the Contec the best all-around pulse oximeter for general wellness use. While we didn't compare these pulse oximeters to actual arterial blood gas (SpO2) numbers (the gold standard for testing oxygen levels), others have. A 2016 study in Anesthesia & Analgesia found that the Contec met the International Organization for Standardization (ISO) criteria for accuracy when used on healthy subjects. It's also approved by the Food and Drug Administration, gave us fast and consistent readings in our tests, and reacted quickly to oxygen changes during our breath-hold testing. We appreciate the pulse rate bar graph as well, which lets you know if your blood flow is high enough to get a good reading. It helps that the Contec is fairly comfortable and incredibly easy to use. Just place it over your fingernail, press the power button and wait for a reading. It turns off automatically and quickly when you're done.
While Contec claims that it will support 30 hours of continuous use, it's only meant for spot checks, so you won't really notice. It also doesn't store and chart your oxygen levels and pulse rate changes like some of the higher-tech versions we tested. A Nonin (read: competitor sponsored) study found that the Contec struggles to accurately detect low oxygen levels in patients with cold hands (cold hands are more likely if you're sick.) Of course, this device is not marketed as, or meant to be, a medical device. What it does do, is help athletes nerd out over their body metrics or to help plane pilots or passengers track oxygen levels. If you want to track your SpO2 levels while you're healthy, this is the one for you.
The Nonin Onyx Vantage 9590 is the only pulse oximeter we tested that is considered medical-grade and may require a prescription. A study in the European Respiratory Journal compared Nonin readings to actual arterial readings on 94 patients. The Nonin's readings correlated quite well, the best of the three pulse oximeters tested, giving us more confidence in its readings. Because of this study, we used the Onyx as a benchmark in our accuracy testing. It performed consistently and provided the most rapid results in the test, with an average response time of just over 3 seconds. It is also the only device that claims to work well with all skin tones, for patients with poor circulation, and even for those wearing fingernail polish.
Studies show that pulse oximeters can dangerously overestimate oxygen levels in a percentage of very sick patients, and they are more likely to do so with dark-skinned patients. Nonin claims they have solved this issue, citing a study showing that the Onyx only significantly overestimates oxygen levels when they fall below 70%. Since normal oxygen saturation is 95% or above, it did a better job of catching early SpO2 dips than the other two options tested. We didn't notice any difference in the readings between our dark-skinned and light-skinned testers, though they were all healthy with normal blood flow and oxygen levels. Pulse oximeters tend to work well under those conditions. The only downsides we uncovered are that this device is expensive, doesn't record any of your data, and may require a prescription. If you want a medical-grade device, ask your doctor about this one.
A 2020 study in The New England Journal of Medicine found that hospital-grade pulse oximeters were three times as likely to miss low oxygen levels in Black patients than in light-skinned patients, missing it in around 11% of Black patients and 4% of White patients.The New York Times ran an article responding to the 2020 study. They interviewed doctors who argued that pulse oximeters can still be a useful tool to monitor oxygen levels as long as you understand their limitations. It's a good idea to reach out to your doctor for more information on these complex topics.
The ViATOM Bluetooth Wrist Monitor is meant for continuous oxygen saturation monitoring while you sleep. It snaps on like a watch with a small and flexible finger loop. The result keeps weight off your finger and is very comfortable. The ViHealth app captures and charts your data while you rest (as long as you leave it on for over two minutes). The app is not the most user-friendly, but it doesn't take long to master and provides plenty of information, letting you set vibration alerts if your SpO2 or pulse rate falls below or rises above certain thresholds. During breath-hold testing, the ViATOM vibrated every time our freediver tester experienced hypoxic contractions. A USB cable recharges the device.
Though the ViATOM provided consistent and accurate readings for all of our testers, it did take twice as long to register the first reading for our Black tester than our White testers. Since it's meant to monitor over a longer time period, the extra 10 seconds isn't a big deal, but it does give us pause. The ViATOM also has many small pieces, is harder to put on, and is more delicate than many of the other options. The finger loop is one-size-fits-all, which may not accommodate all fingers, and it's expensive. If you need to monitor your oxygen levels while getting a good night's sleep, though, it could be the one for you.
The Innovo Deluxe monitor is a comfortable and reliable option that performed well in all of our tests. We appreciate how easy it is to use. Just insert the included batteries, and it quickly reads your SpO2, pulse rate, and perfusion index (PI). At the same time, it gives you plenty of customizable options. You can set up high and low SpO2 or pulse rate alarms, turn on a (really annoying) alert beep, adjust the display brightness, and rotate the display readout to face you or a care nurse — all by manipulating its one power button. (Keep those instructions handy.)
The display also helps you determine how reliable the readings are. If the perfusion index is below 0.3%, you may not have enough blood in your hands for an accurate reading. You should warm them up with a cup of tea or a quick walk around. Similarly, the pulse rate bar should be above 30%, and the plethysmograph waveform, which measures your blood flow, should show consistent wave heights before you trust a reading. This device feels exceptionally sturdy, and we appreciate that it helps you get an accurate reading. If you don't need an app to record your readings, the Innovo Deluxe is a high-quality option.
The Masimo MightySat delivers a wealth of health information quickly and consistently. It tracks more data than any other device in our test, including blood oxygen saturation (SpO2), pulse rate, respirations per minute, perfusion index (PI), and pleth variability index (PVi), which can be used to help manage fluid intake. Its SpO2 and pulse rate measurements were comparable to the other devices we tested. It stores all of this data via the Masimo Personal Health App, and you can change the readout orientation on the device by tapping the bottom of the display. What we really love about this option is its comfort. Its clever hinge and wide shape distribute pressure evenly across a padded cradle.
We expected a lot based on this unit's price, and you do get more data with the MightySat, but if you don't know what those health metrics mean, they don't do you a lot of good. And despite the impressive data collection, this is not a medical device. It also reacted slower than the Contec during our breath-hold testing and didn't seem to register oxygen readings below 90%. While we liked the iPhone version of the app, the Android option is more difficult to use. Our biggest complaint with the MightySat, though, is its huge price tag. Still, if you want an extremely comfortable device for quick check-ins on important health metrics, this one might be a good choice for you.
It took us a while to make out the expressive polar bear beneath the frosted protective cover of the Zacurate Children. Designed as a wellness check device for children 2-12 years old, the cuteness is intentional. Other than the kid-friendly facade and very small finger port, this non-medical device works much the same as the other fingertip devices. It's meant for quick oxygen level check-ins. Simply press the polar bear's nose (we love this), let him eat your finger, and you'll have a SpO2 and pulse rate reading in about seven seconds.
The device also gives you a waveform to help you gauge how consistent your kiddo's blood flow is and thus how accurate a reading is likely to be. The device is quite small by necessity, and we often struggled to get it to register our adult hands, even using our pinkies. However, when it did, its readings were consistent and in line with the most accurate devices we tested. This is a good option for anyone looking to get tabs on their child's oxygen stats.
The AccuMed Fingertip is another simple fingertip option. It lets you know if you have adequate blood flow for a reading with a pulse bar and waveform. We appreciate the protective rubber cover and the comfortable finger bay. It performed well in all of our consistency and accuracy tests.
The AccuMed does take a little longer to get a reading than most of the options we tested, averaging around 12 seconds. We're rarely so busy that we can't spare that amount of time, though. Remember, this device is meant for speedy spot checks to inform athletics and general wellness, and AccuMed warns against using it for over two hours, which could disrupt your blood flow. You can't do things like change the direction of the display or its brightness, but the streamlined AccuMed gets the job done.
The MiBest OLED Finger Pulse is lightweight, plenty comfortable, and offers a no-nonsense approach to collecting basic health data. Just press the power button and the screen comes to life, giving you your pulse rate and blood oxygen saturation in about 6 seconds. It's easy to read, and you can adjust the screen brightness and orientation quickly using the power button. A pulse bar graph on the left side of the display lets you know if the device is getting adequate signal strength. In our tests, its readings were consistent and in line with the most accurate options in the review.
The MiBest is of the most basic options in our review. It doesn't include an alarm to alert you if your oxygen levels or pulse rate drop to concerning levels like some of the other options. It also doesn't record any of your data. Since it's intended as a spot-check device for sports, that makes sense. This is the most basic device available at an approachable price.
The Santamedical Dual Color OLED delivers basic health information without overwhelming you. It quickly and reliably provides readings with the push of a button, and the data comes through in under 10 seconds. It also provides a pulse bar, which should be over 30%, and waveform, which should be consistent, to let you know when there is enough data for an accurate reading. You can rotate the display to face whatever direction you choose.
This isn't the most comfortable device in our review. The rigid plastic finger cradle and simple hinge provide very little give. Other than that, it's another solid option for quick, simple spot checks. Anyone looking to monitor their pulse rate and oxygen saturation levels without learning their way around new technology will likely appreciate this affordable option.
The Wellue O2Ring is comfortable, easy to use, and easy to wear. It also captures, charts, and catalogs time-stamped data via the ViHealth app. It gave us consistent and reactive readings in our tests, shifting quickly in response to an inhale after a long breath-hold during our hypoxic testing. Our freediving tester also appreciated that the ring vibrated a warning every time he experienced contractions (which are normal for breath-holding athletes). You can adjust the Sp02 alert in the app (we set ours to 88% during testing), and it worked consistently in our normal use tests as well.
The reactiveness of the Wellue can make the ring itself difficult to read, and it falls asleep quickly. It's easier to track readings on the app. Since its small size makes it easy to lose track of, we worried that we would accidentally damage it, and it's not cheap. The ring also registered lower oxygen saturation readings on average than the other models, with an overall average of 96%. The rest were 98% or above. That said, many experts recommend using these devices to get a sense of what is normal for you and then watching for upward or downward trends, so the ring will still give you valuable information. Its comfort and data capture makes it appealing, its price tag and lower SpO2 readings do not.
The Zacurate Pro Series 500DL comes with a non-slip casing that protects it from wear and tear while providing a solid grip. This device is simple, measuring just your pulse rate, the strength of your pulse (to help you get an accurate measurement), and your oxygen saturation percentage. Its features match its lower price tag. We found its readings reliable and comparable to the highest-rated models we tested.
The Zacurate was consistently slower to pick up readings for our Black tester than for our White testers, though, taking an extra 15 odd seconds to read on average. The extra time isn't a huge deal, but it does make us wonder if it works as well on darker skin tones. This unit also only measures pulse rate and SpO2. If that is all you're seeking, and you have lighter skin, you'll find this oximeter perfectly agreeable.
The iHealth Air Wireless offers a sleek aesthetic and a comfortable finger port. The bright green LED display makes it easy to read your SpO2 and pulse rate measurements. When tethered to your smart device, you can also see your perfusion index via the iHealth app, which helps you understand how reliable your readings are. The app itself is bright, pleasing to the eye, and easy to navigate and understand. You can also sync with the iPhone health app for an even more complete snapshot of your health. The device itself can store up to 100 measurements internally that will transfer to the app whenever you reconnect to your phone. It's rechargeable via a USB cable.
Our biggest concern with this device is how often the display blanks out. It reads quickly, in an average of 6 seconds, but then routinely stops for minutes at a time. More concerningly, it seemed to happen more often with our Black tester. During one test, the iHealth only gave us one quick and abnormally low reading (94%) for her before blanking out for over 2.5 minutes. Many of the devices do this from time to time, but we noticed it much more often with the iHealth. While the monitor is sophisticated, the hinges have some lateral instability, making the device feel fragile. You also have to hold your hand palm up to read the monitor. It's the only device that requires this, and we find it uncomfortable and tiring. Though the iHealth will give you a very quick spot-check, it usually takes a moment or two for readings to stabilize, and by then, it is often blank again. It's not our favorite option.
Why You Should Trust Us
This review is headed up by Clark Tate, an avid athlete who loves data. Clark held a Wilderness First Responder certification for a decade and has a Master's Degree in environmental science. Her comfort reviewing scientific research and monitoring vital signs helped her test and compare these devices. Clark also consulted with a professional freediver, Ryan Reed, to test them in hypoxic conditions. Clark has light skin, so she recruited a local business owner, Michele Morris, of Woolly Jumper Yarns to test the pulse oximeters on Black skin and to provide another perspective on how easy and comfortable each model is.
After reams of research, we rounded up 12 of the most popular pulse oximeters on the market to test extensively. The team checked their oxygen saturation during multiple rounds of testing while at rest, taking averages and timing how long each display took to get its first reading. We also tested them during dry static apnea training for freediving, with breath holds lasting up to 3 minutes and 45 seconds and oxygen levels dropping down to 80%. Then we tested each device against the Contec and Nonin options, which have research-backed accuracy levels. Afterward, we assessed them consistently, took notes on ease of use, and compared their comfort and features.
Analysis and Test Results
We gathered real-world data from healthy testers to identify the most outstanding pulse oximeters for your needs. Our detailed data and use notes helped us compare the devices head-to-head. Below, we expand upon each of our testing metrics, outlining which models excelled in each area.
To know your true oxygen saturation rate, you need to get a blood sample from an artery to find your arterial blood gas. This is a painful and somewhat risky procedure, and we did not test these pulse oximeters by this high standard. But others have, and have found that the Contec and Nonin both provide more accurate readings than most when blood oxygen levels are low. Of the two, the Nonin Onyx has more research backing its efficacy. There is also some research backing its claim that it provides more accurate readings for those with darker skin tones. It is an FDA-approved medical device, the only one in this review. The rest are meant for wellness checks for athletes or aviation use. That is, they're meant to be used by relatively healthy people and are not medical devices.
Considering the research, we rank the Nonin Onyx as the most accurate monitor in our review, followed by the Contec. When we tested each monitor against these two standards, all of them gave us comparable oxygen saturation numbers within one percentage point. We tested this by attaching all three monitors to a finger on one hand, then took several readings before rotating them through the different fingers to account for any circulation issues. Bottom line, we consider them all fairly accurate on healthy people with good circulation.
While pulse oximeters may be useful for estimating blood oxygen levels, these devices have limitations that can result in inaccurate readings. Patients with conditions such as COVID-19 should not rely solely on pulse oximeter measurements to monitor their health at home as they are not a substitute for a medical diagnosis by a health care provider.We think the same New York Times article that responds to the pulse oximeter racial bias study provides a useful counterpoint.
When we averaged readings from our standard tests, most of the devices were quite similar, giving us average readings of 98% or 99%. The average for the Wellue O2Ring was 96% for the same people measured at the same times. If you go for that one, just know it tends to run a bit lower than other options. The iHealth total was also a bit low at 97%, largely because it was so often blank during our tests.
We did test the device's performance in hypoxic events on light-colored skin with the help of a professional freediver, who conducted several rounds of dry static breath-hold training with each device from 2.5 to 3.5 minutes. We tested the devices in pairs to have a comparison point, and most dipped to between 80% to 88% SpO2. The Wellue O2Ring dipped down to 74%, and the Masimo stayed at 90% or above. The Wellue, Contec, ViATOM, and Innovo were more reactive than the others, tracking changes more closely.
Most of these devices are meant for spot-checking your oxygen levels. But even if you just have the device on your fingertip for a minute or two, it helps if it's comfortable. If you need or want to monitor your oxygen level trends over time, you'll definitely appreciate not feeling like your finger is in a vice.
The Wellue O2Ring and ViATOM Wrist monitors are both meant for sleep monitoring and are exponentially more comfortable than their fingertip clip counterparts. Of the two, we prefer the wrist monitor since it divides its weight and bulk between your finger and wrist. Still, we don't mind sleeping in either or wearing it for hours.
Of the fingertip monitors, the MightySat is far and away the most comfortable. The hinge doesn't hold pressure on your fingertip, spreading it evenly across your first two joints instead. The cushioned port is delightful. It's the only hinged monitor we would want to wear for any amount of time.
Most of the rest are fine. Certainly comfortable enough for a speedy spot check. The Nonin and Contec monitors are some of the least comfortable in the review. They are short and don't distribute pressure very well, leaving us with sore fingertips that feel like they've lost a little circulation. We don't love the iHealth either, since it forces us to find a comfortable palm-up resting position.
Ease of Use
Generally, pulse oximeters have user-friendly interfaces. That said, we tested units that fall across the spectrum from high-tech to superbly simple. While we wouldn't say that any of these are difficult to use, the four options that link to your smart device via Bluetooth to provide app support are certainly more complex. The ViATOM Wrist and Wellue O2Ring options both use the same ViHealth app. We found it easy enough to navigate even when toggling between the two devices. It clearly displays readings in real-time and makes it easy to scroll through your history. The readouts on the devices themselves are harder to see.
We struggled more with the Masimo Personal Health app. It doesn't catalog past recordings clearly by date. It works well in real-time, though, and the display on the device is large, easy to read, and rotates to face either you or a caretaker. The iHealth app is bright and cheery and maps long-term trends for you. We also like the on-device display. The problem with this pulse oximeter is how often the display blanks out on you.
Of the app-free options, the Nonin is the easiest to use. It turns on automatically when you insert your finger and offers the fastest response time, giving you a reading in just over 3 seconds on average. The rest are similarly simple — you just need to press the power button first. We really appreciate the Innovo, Mibest, Santamedical, and Zacurate Children options that let you rotate their display so it's easy for you to look at it no matter what finger you place it on.
All of these pulse oximeters measure your blood oxygen saturation and pulse rate. Quite a few include more detailed information. The Masimo MightySat offers the most comprehensive health data, especially when compared to the more simplistic machines we reviewed. This model measures SpO2, pulse rate, perfusion index (PI), respiration rate (RRp), and pleth variability index (PVi) and stores everything in its companion app.
Having an app to store your data is a big plus, particularly if you're not good at documenting your own measurements. They also emphasize interesting data like any concerning oxygen level drops. For that reason, we rate the MightySat, the Wellue O2Ring, the ViATOM Wrist, and the iHealth options high in the features category.
A number of these devices also give you additional information — like a perfusion index score, a pulse rate bar, and a waveform photoplethysmograph — to help you determine if you're getting enough blood flow for a good reading. The Innovo monitor gives you all three indications, as does the MightySat. The AccuMed and Santamedical give you the pulse bar and the waveform. The iHealth gives you your perfusion index in its app readout, and the Nonin, Contec, Mibest, and two Zacurate options provide a pulse bar.
Basic models offer just a couple of data points. Fancier devices often provide more. To understand the data, you'll need to know these abbreviations:
- SpO2 stands for oxygen saturation. SpO2 measures the amount of oxygen in your blood at a given time. It is measured as a percentage of the total oxygen your blood is capable of carrying.
- PR or HR stands for pulse rate or heart-rate, respectively. They are interchangeable and describe how many times your heart beats every minute. Your PR will change constantly based on your body position, activity level, or emotional state.
- PI or perfusion index describes how much blood is in your non-pulsatile or peripheral tissues. A low PI number may indicate that you don't have enough blood flow for an accurate reading.
- PVi is pleth variability index and measures the variability of the pleth (short for photoplethysmograph) waveform (the waves that show up on the bottom of some of the monitor displays) and the changes that occur with respiration. The pleth waveform indicates the strength of your pulse and how much blood is moving through your capillaries.
- Brpm stands for breaths per minute or respiratory rate. It measures how many breath cycles you take every minute. It can reflect how well your heart and lungs function in day-to-day movement or in recovery from exercise.
To gauge durability, we rolled these devices around on our fingers, tugged on the hinges, and looked closely at the battery door tabs. In general, these are robust devices that will perform their task reliably if you treat them as well as you would a smartphone. The fingertip monitors seem more robust than the two wearable options. Both the ViATOM and Wellue have a ring monitor that is not meant to be compressed, so don't sit on them or toss them in a bag. We saved the boxes they came in for safekeeping.
Of the clip-style monitors, Innovo strikes us as particularly robust and well made. Its battery door tabs and hinges are easy to operate, the hinge is well-contained, and the plastic feels very sturdy. We are pleased with how the screen absorbed inevitable scratches and wear. The Nonin seems similarly bombproof, with a pleasant spring on its battery door and scratch-free facade. We also appreciate that the AccuMed and Zacurate options come with protective rubber covers.
Most of the remaining monitors give us little cause for concern, though the screen on the Contec ended up with more scratches than the rest, and the AccuMed received a few too. And, while the MightySat seems very well-made, the battery door is hard to open and seems like it could be easily broken. The iHealth hinges chatter edquite a bit, and it often closed a little out of line.
The quest for a pulse oximeter can feel complicated given the scientific jargon and many abbreviations. We're here to help. To pick the best monitor for your needs, first, figure out when you'll use it and why. From there, you can decide which features are right for you.
— Clark Tate